It is known that pieces, such as cylindrical paper rolls, are wrapped by using wrapping apparatuses which perform the wrapping by means of a wrapping film, preferably a transparent stretch film. These wrapping apparatuses normally use a thin plastic film which is guided around the piece while the piece is rotated around its central line. It is also known to transfer the wrapping apparatus in the direction of the central line to wrap the whole envelope surface of the piece with several layers of the wrapping film. As to the techniques involved in cutting, sealing and feeding of the film, reference is made to U.S. Pat. No. 5,092,109. During the wrapping, the wrapping film is also stretched in a controlled way, as presented in U.S. Pat. No. 5,054,263.
Forming roll packages comprise several film layers and protective layers which protect the roll material, roll ends, and particularly the roll edges. Packages of prior art are presented in U.S. Pat. No. 5,890,591, in which the first film layer is a film wrapped in the axial direction. The second layer is padding, and the third layer is a film wrapped in the spiral and radial direction. According to U.S. Pat. No. 5,850,918, the padding placed around the roll end and on the roll edge is foam plastic or bubble pack plastic. One wrapping apparatus for radial wrapping is presented in U.S. Pat. No. 4,736,567, whereby films can be fed on the roll in an interleaved manner. One roll package for a sensitive material is presented in U.S. Pat. No. 5,873,464. The package comprises a bubble pack layer and a film layer extending over the ends of the roll in an interleaved manner. Protective pieces are placed at the ends of the roll. One apparatus for axial wrapping is presented in U.S. Pat. No. 4,281,500. The rotation is performed by means of rolls fitted in a rotating table.
During transportation and manipulation, rolls are susceptible to mechanical damage, wherein particularly their edges must be well protected e.g. with padding. The roll can also be damaged during the manufacture by machine transfers and manipulation between separate wrapping apparatuses, and by the film itself, stretched around the roll. Thus, the layers protecting the roll should be fitted in such a way that they protect the roll efficiently at all stages. By placement of the layers, a tight package should be achieved, to prevent the effects of soil and moisture.
In the order of wrapping the layers of the roll, one must take into account the apparatuses available for wrapping, which are often simple automated devices and are often separate, as well as their phasing, wherein there should be as few transfers of the roll as possible. Separate wrapping devices can comprise the axial wrapping of a single layer, the radial wrapping of a single layer, or these wrappings combined.
The present invention is directed to an improved roll package and a method of manufacturing an improved roll package. In one embodiment of the invention the roll package comprises three layers. The layers are placed crosswise on top of each other. In another particularly advantageous embodiment of the invention, the improved roll package comprises a set of rolls which are first wrapped separately and then wrapped together for forming one roll package. Thus, in one embodiment of the invention the roll package comprises four layers, wherein the fourth layer binds the separate rolls together. Also in this case the layers are placed crosswise on top of each other.
The roll package comprises a first layer which is a protective layer and which is wrapped in the radial direction. In one embodiment, the layer is a foam layer, preferably foam plastic, or a bubble pack layer. The bubble pack layer is for example of a material in which small air cushions are closed between two plastic layers. If necessary, the protective layer is bent over the roll edge to cover the roll end at least partly. In one embodiment, the protective layer comprises separate portions which are placed on the roll mantle by the side of the ends. The second layer is a plastic film which is wrapped preferably in the axial or in the radial direction. It keeps the first layer in its position and is placed tightly against the roll. The axial wrapping protects the roll uniformly, also the end of the roll. It adheres effectively to the material of the second layer, forming a very tight roll package. The third layer is wrapped on the roll mantle, but in one embodiment, it is also extends over the roll edge in a tightening manner, covering the end of the roll at least partly. Alternatively the second layer is a plastic film layer wrapped axially or a craft paper for forming a durable and opaque layer, which forms the outermost surface of the roll.
The improved roll package comprising a set of wrapped rolls having at least two layers is particularly adaptable for forming multi-packages. The rolls can be transported in one larger package. Single rolls can be separated from the package, but in spite of this, they are each protected with at least two layers from damage. The package thus comprises a separate layer which is a plastic film wrapped axially over all the rolls and the layers. Thanks to the tight plastic film, adjacent rolls are tightly supported to each other by means of axial wrapping. The movement of the rolls against each other is made more effective by rotating the rolls around their common longitudinal axis during the wrapping. The ends of the rolls are against each other.
The roll ends are protected by axially wrapped second layer or by axially wrapped third layer. Alternatively, the roll ends are protected by radially wrapped second layer and two circular end covers. The end covers are applied on said roll ends covering them entirely. Alternatively, the roll ends are protected by radially wrapped second layer, wherein the second layer is a craft paper, and circular end covers. Devices for applying the end covers on the roll ends are known as such.
If the width of the material of the first layer is smaller than the length of the roll, it can be fitted around the roll in a spiral manner. In one embodiment, the first layer comprises several lengths fitted next to each other which are attached and cut and which extend at least one circumference around the roll mantle. The material is supplied as a band from one or more material rolls of the wrapping apparatus, wherein the bands can also be placed in a partly overlapping manner.
The apparatus required to apply the method for forming a roll package comprises a first radial wrapping device for said first layer, an axial wrapping device, and a second radial wrapping device. In connection with these devices, the roll is rotated in its position by rollers around a horizontal longitudinal axis. The second radial wrapping device and the axial wrapping device can be arranged in connection with the same rotating device, wherein the roll does not need to be moved. Between the first and the second device, the roll is moved on top of a controlled movable carriage which lifts up the roll and descends it on top of the rollers. When making multi-packages, single packages are moved from the second device by a carriage and first collected into an intermediary station from which they are returned together for axial wrapping. Said axial wrapping device is also used for the wrapping of said separate layer.